Strategies.- Chemical Construction of Immunotoxins.- Construction of Ribonuclease–Antibody Conjugates for Selective Cytotoxicity.- Intracellular Targeting Using Bispecific Antibodies.- Antibody Conjugation Methods for Active Targeting of Liposomes.- Folate as a Targeting Device for Proteins Utilizing Folate Receptor-Mediated Endocytosis.- Preparation of Recombinant RNase Single-Chain Antibody Fusion Proteins.- Theoretical Aspects.- Practical Considerations in the Exploitation of Passive Tumor Targeting.- Effect of Dose, Molecular Size, and Binding Affinity on Uptake of Antibodies.- Inhibition of Tumor Blood Flow.- Applications.- 10 Targeting in Myocardial Infarction.- 11 Targeting HIV-Infected Cells.- 12 Making Fusion Toxins to Target Leukemia and Lymphoma.- Antibody-Bearing Liposomes as Chloroquine Vehicles in Treatment of Murine Malaria.- 14 Immunotargeting of Catalase to the Pulmonary Vascular Endothelium.- 15 Targeted Gene Transfer.